The present invention is directed to a novel and improved exhaust gas and vacuum tracking carburetor jet for installation in an internal combustion engine. The invention tracks both the exhaust gas emission temperature and intake manifold vacuum. The object of the invention is to achieve the optimum fuel-air combination for the conditions tracked. In response to temperature variations in the exhaust gas and vacuum differences in the manifold fuel is metered between the fuel chamber and fuel/air mixing chamber. The metering occurs in direct proportion to the changes sensed. As the temperature of the exhaust gas rises and/or the intake minifold vacuum decreases the system detects these changes and causes a metering orifice between the two chambers to expand allowing additional fuel to traverse. When the temperature decreases or vacuum increases the metering orifice shrinks cutting down on the supply of fuel. High exhaust gas temperatures indicate too lean a fuel/air mixture or increasing power consumption. While a decrease in the manifold vacuum is indicative of an engine under an increasing load. The invention compensates for these conditions by adjusting the fuel/air mixture. Through the years several mechanical devices have been presented.
For example, U.S. patent application Ser. No. 970,994 to Muscatell describes the simultaneous monitoring of an internal combustion engine's exhaust gas and intake maifold vacuum to mechanically meter fuel to the carburetor in order to enrich or lean the fuel/air mixture to the optimum ratio.
U.S. Pat. No. 3,263,974 to Braun shows a carburetor system in which the fuel/air mixture is enriched when the engine temperature is low, referring to this as "cold weather enrichment". In addition, the system of this patent enriches the fuel/air mixture when the intake manifold vacuum drops during high power demand or the engine, such as when the vehicle is being accelerated.
U.S. Pat. No. 4,192,140 to Yamashita illustrates a two-stage response when the engine vacuum at the intake increases in response to closing of the throttle valve when the vehicle decelerates. In the first step the fuel/air mixture is made leaner by adding more air and in the second step after a time delay of 1 or 2 seconds additional fuel is introduced into the fuel/air mixture. In the Yamashita invention when the engine intake vacuum increases the fuel/air mixture is leaned and after a brief delay is enriched.